'Alien Megastructure' Star Is at It Again with the Strange Dimming

[Dryson]

Tabby's Star is now 3% dimmer than its earlier recorded dims of 2015.

The perplexing cosmic object known as "Boyajian's star" is once again exhibiting a mysterious pattern of dimming and brightening that scientists have tried to explain with hypotheses ranging from swarms of comets to alien megastructures.

Today (May 19), an urgent call went out to scientists around the world to turn as many telescopes as possible toward the star, to try and crack the mystery of its behavior.

"At about 4 a.m. this morning I got a phone call … that Fairborn [Observatory] in Arizona had confirmed that the star was 3 percent dimmer than it normally is," Jason Wright, an associate professor of astronomy at Pennsylvania State University, who is managing a study of Boyajian's star, said during a live webcast today at 2 p.m. EDT (1800 GMT). "That is enough that we are absolutely confident that this is no statistical fluke. We've now got it confirmed at multiple observatories, I think."

http://www.space.com/36925-alien-me...l&utm_source=facebook.com&utm_campaign=buffer


Hopefully the JWST and the WFIRST satellites will be able to provide a more detailed account of what is taking place with KIC 8462852 when they are launched.


Here is the reddit page linked by Tabby herself as the place to go get the correct information.
https://www.reddit.com/r/KIC8462852/

A live stream feed of Dr. B taking Q and A about three hours ago.

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[PurpleBuddha]

Nice. They predicted a drop in May this year.

 

[Crazy Eddie]

Nice. They predicted a drop in May this year.

And here's the abstract from that very paper:

Over the duration of the Kepler mission, KIC8462852 was observed to undergo irregularly shaped, aperiodic dips in flux of up to ∼20\%. The dipping activity can last for between 5 and 80 days. We characterize the object with high-resolution spectroscopy, spectral energy distribution fitting, radial velocity measurements, high-resolution imaging, and Fourier analyses of the Kepler light curve. We determine that KIC8462852 is a typical main-sequence F3 V star that exhibits no significant IR excess, and has no very close interacting companions. In this paper, we describe various scenarios to explain the dipping events observed in the Kepler light curve. We confirm that the dipping signals in the data are not caused by any instrumental or data processing artifact, and thus are astrophysical in origin. We construct scenario-independent constraints on the size and location of a body in the system that is needed to reproduce the observations. We deliberate over several assorted stellar and circumstellar astrophysical scenarios, most of which have problems explaining the data in hand. By considering the observational constraints on dust clumps in orbit around a normal main-sequence star, we conclude that the scenario most consistent with the data in hand is the passage of a family of exocomet or planetesimal fragments, all of which are associated with a single previous break-up event, possibly caused by tidal disruption or thermal processing. The minimum total mass associated with these fragments likely exceeds 10−6~\mearth, corresponding to an original rocky body of >100~km in diameter. We discuss the necessity of future observations to help interpret the system.​

The paper goes on to say:

[the dust cloud] scenario therefore pre-
dicts that KIC 8462852 may now have a large mid-IR excess, but
the most recent IR observations taken in 2015 January with Spitzer
IRAC show no significant excess for KIC 8462852 (Marengo et al.
2015). However, non-detection of an excess would not necessarily
rule this scenario out, as the dust levels derived in Section 4 (which
account for the dust seen passing in front of the star) were shown
to be consistent with a non-detection. A more robust prediction is
that future dimming events should occur roughly every 750 days,
with one in 2015 April and another in 2017 May.​

It later adds in their conclusions:

A broad range of scenarios for the dipping behavior that in-
volve occultation by circumstellar dust clumps was considered.
Among these, we find that the break-up of one or more massive
exocomets (or planetesimals on comet-like orbits) provides the
most compelling explanation consistent with the data in hand. The
required mass of the original body may have been in excess of
3×10^21grams (only ~0.3% the mass of Ceres, and perhaps
~100km in diameter)​

So the team that discovered it is pretty solid in the comet fragment theory, and they've made an accurate prediction about the orbital characteristics of the object in question. So we can place an early bet on what this next set of observations is probably going to show.

 

[Dryson]

Quote

"I heard that (on twitter) there are no hydrogen lines (how could that be? there should be Balmer lines and other hydrogen lines in the star's SED), no sodium lines, no calcium lines. These rule out the comet swarm hypothesis (how?) and the interstellar gas hypothesis. Well, regardless of the truth of the news, let's assume they are true. Then what could this mean? Will we be facing an artificial megastructure?"

https://www.reddit.com/r/KIC8462852/comments/6cgbao/what_could_this_mean/

 

[Crazy Eddie]

Quote

"I heard that (on twitter)...

Everything after this was irrelevant.